Sulfur Plasma Lamp

Abstract

A sulfur plasma lamp has a lamp envelope of transparent or translucent glass or ceramic material. At least two silicon carbide electrodes are hermetically sealed with the lamp envelope and in contact with an interior of the lamp envelope. A quantity of sulfur within the interior of the lamp envelope is sufficient to create a sulfur plasma upon excitation. A buffer gas within the interior of the lamp envelope enables initial discharge and heating of the interior of the lamp envelope to excite the sulfur into a plasma state. More than two electrodes may be provided, and an electrical potential is created between different pairs of the electrodes at different times, thereby inducing stirring of the plasma upon excitation of the material into a plasma state.

1 . A plasma lamp, comprising:
 a lamp envelope of transparent or translucent glass or ceramic material;   at least three electrodes hermetically sealed with the lamp envelope and in contact with an interior of the lamp envelope, each of the at least three electrodes being substantially evenly spaced relative to a closest other one of the at least three electrodes;   a quantity of material within the interior of the lamp envelope sufficient to create a plasma upon excitation; and   a buffer gas within the interior of the lamp envelope for enabling initial discharge and heating of the interior of the lamp envelope to excite the material into a plasma state; and   a single-phase power supply connected to each of the at least three electrodes.   
     
     
         2 . A method of operating a plasma lamp, comprising:
 providing a plasma lamp comprising:
 a lamp envelope of transparent or translucent glass or ceramic material; 
 at least three electrodes hermetically sealed with the lamp envelope and in contact with an interior of the lamp envelope, each of the at least three electrodes being substantially evenly spaced relative to a closest other one of the at least three electrodes; 
 a quantity of material within the interior of the lamp envelope sufficient to create a plasma upon excitation; and 
 a buffer gas within the interior of the lamp envelope for enabling initial discharge and heating of the interior of the lamp envelope to excite the material into a plasma state; 
   providing a single-phase power supply connected to each of the at least three electrodes; and   driving the plasma lamp by firing the power supply across different pairs of the at least three electrodes at different times, repeatedly switching between the different pairs at a fixed rate.   
     
     
         3 . A method in accordance with  claim 2  wherein the switching occurs at a rate of at least a couple of dozen hertz. 
     
     
         4 . A method in accordance with  claim 3  wherein switching occurs in the kilohertz range. 
     
     
         5 . A method in accordance with  claim 3  wherein switching occurs in the megahertz range. 
     
     
         6 . A method in accordance with  claim 2  wherein the repeated switching between the different pairs of the at least three electrodes induces stirring of the plasma.